搜题请搜索小程序“爱下问搜题”
问题 填空题

为了减缓二氧化碳使全球变暖的趋势，有些科学家提出大胆设想：将排放到空气中的二氧化碳压缩使其液化，然后将其压入到冰冷的深海中．但也有些科学家担心海水中富含二氧化碳后酸度会增加，可能会杀死一些海洋生物…．请你回答下列问题：

①二氧化碳气体转变为液体时将会______能量（填“释放”或“消耗”）；

②二氧化碳使海水酸度增加的原理用化学方程式表示为______；

③二氧化碳在深海中的溶解度比在通常状况在水中的溶解度______（填“大”或“小”），原因是______．

答案

（1）二氧化碳由气体转化为液体，可以将其中内能释放出来，因此液化过程是放热过程；故填：释放

（2）二氧化碳使海水酸度增加，是因为二氧化碳与水反应生成碳酸，其化学方程式为CO2+H2O=H2CO3；

（3）气体的溶解度规律是：在温度一定时，压强越大气体溶解度越大；在压强一定时，温度越低气体溶解度越大．

故填：大、；压强大，温度低；

单项选择题

Most plants can make their own food from sunlight, (1) some have discovered that stealing is an easier way to live. Thousands of plant species get by (2) photosynthesizing, and over 400 of these species seem to live by pilfering sugars from an underground (3) of fungi(真菌). But in (4) a handful of these plants has this modus operandi been traced to a relatively obscure fungus. To find out how (5) are (6) , mycologist Martin Bidartondo of the University of California at Berkeley and his team looked in their roots. What they found were (7) of a common type of fungus, so (8) that it is found in nearly 70 percent of all plants. The presence of this common fungus in these plants not only (9) at how they survive, says Bidartondo, but also suggests that many ordinary plants might prosper from a little looting, too.

Plants have (10) relations to get what they need to survive. Normal, (11) plants can make their own carbohydrates through photosynthesis, but they still need minerals. Most plants have (12) a symbiotic relationship with a (13) network of what are called my corrhizal fungi, which lies beneath the forest (14) . The fungi help green plants absorb minerals through their roots, and (15) , the plants normally (16) the fungi with sugars, or carbon with a number of plants sharing the same fungal web, it was perhaps (17) that a few cheaters—dubbed epiparasites—would evolve to beat the system. (18) , these plants reversed the flow of carbon, (19) it into their roots from the fungi (20) releasing it as "payment.\

17（）

A.essential

B.important

C.possible

D.inevitable
查看答案
单项选择题

奶作为学龄前儿童钙的最佳来源，适宜的饮用量为每天（）。

A.1000ml

B.至少250m1

C.300ml以上，越多越好

D.250～400ml
查看答案